| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.91 |
| Score | 0% | 58% |
The advantage of using a third-class lever is that it increases:
the speed of the load |
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the distance traveled by the load |
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the mechanical advantage of the lever |
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the force applied to the load |
A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.
The science that deals with motion and the forces that produce motion is called which of the following?
engineering |
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aeronautics |
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mechanics |
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physics |
Mechanics deals with motion and the forces that produce motion.
Which of these is the formula for force?
F = ma |
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F = a/m |
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F = am2 |
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F = m/a |
Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration.
Sam can do 50 ft. lb. of work in 2 minutes and 5 seconds. What would Sam have to do to increase his power output?
do the work in 2 minutes |
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do 100 ft. lb. of work in 4 minutes 12 seconds |
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do 25 ft. lb. of work in 2 minutes 5 seconds |
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do the work in 3 minutes |
Power is the rate of doing work or \(\frac{W}{t}\). To increase power, increase the work being done in the same amount of time or do the same amount of work in less time.
Lisa lifts a 25 pound box from the floor onto a loading dock 4 ft. off the ground. Sam slides the same box along a ramp to move it up another 4 ft. onto a flatbed truck. Who has done more work?
Neither have done any work |
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They have done an equal amount of work |
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Sam |
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Lisa |
Work is force multiplied by distance. Because both Connie and Sam moved the same weight the same distance they have done an equal amount of work. Sam employed the mechnacial advantage of an inclined plane so he exerted less effort to do the work but the amount of work done was still the same.